Combustion system for atomizing fuel mixture in burner box

ABSTRACT

A burner system, for burning a liquid fuel/compressed air fuel mixture, comprising a discharge nozzle having a mixing chamber for mixing a liquid fuel with compressed air and discharging the fuel mixture via a discharge orifice. The burner system is coupled to a liquid fuel storage source for storing and supplying the liquid fuel, at a sight positive pressure, to the mixing chamber and the burner system also coupled to a source of compressed air which is supplied to the mixing chamber. An igniter is provided for igniting the fuel mixture, discharged from the discharge orifice in a substantially atomized form, for rapid and through combustion of the fuel mixture. Supplemental air is also supplied, via a variable speed supplemental airfan, to assist with complete combustion of the fuel mixture.

This application is a continuation-in-part of and claims priority from U.S. application Ser. No. 11/768,630 filed Jun. 7, 2007 which is a continuation-in-part of and claims priority from U.S. application Ser. No. 11/657,816 filed Jan. 25, 2007 which is a continuation-in-part of and claims the benefit of U.S. provisional patent application Ser. No. 60/762,551 filed Jan. 26, 2006.

FIELD OF THE INVENTION

The present invention relates to an improved fuel source which is directed at achieving substantially “perfect combustion” of the fuel source so that substantially all of the fuel source is converted into CO₂ and H₂O without any significant amount of unburned hydrocarbons.

BACKGROUND OF THE INVENTION

As is well known in the art, the combustion of most fuels typically results from the combustion of fuel and air whereby the byproducts are typically unburned hydrocarbons, carbon dioxide, nitric oxides, carbon monoxide, and water. One of the drawbacks associated with such combustion is that the unburned hydrocarbons are normally vented to and pollute the atmosphere. In addition, the combustion byproducts tend to leave the combustion chamber in a heated state, thus carrying heat away from the combustion region, thereby reducing the energy efficiency of the combustion system.

A few related known patents are U.S. Pat. Nos. 4,278,412, 5,344,311, 5,921,470 and 6,119,954. U.S. Pat. No. 4,278,412 to Strenekert relates to a process and apparatus for combustion of liquid fuel which provides an extremely intense blue/violet flame. To achieve this, Strenekert discloses mixing the oil and the air with one another to form an oil/air mixture inlet immediately prior to the oil and air mixture being injected from the nozzle front end of the nozzle. That is, the oil and air are mixed with one another immediately prior to the oil and air mixture being ejected from the nozzle.

U.S. Pat. No. 5,344,311 to Black relates to an oil burner having rotary air compresses in which the operating and capital expense, associated with the burner, are reduced by using a compressor which is lubricated with fuel oil supplied for the burner.

U.S. Pat. Nos. 5,921,470 and 6,119,954, both issued to Kamath, relates to a burner utilizing a low pressure fan for atomizing oil and supplying air for combustion. This patent discloses radially injecting the oil into the airstream and mixing the oil with the air prior to the oil and the air exiting from the atomizing nozzle.

SUMMARY OF THE INVENTION

Wherefore, it is an object of the present invention to overcome the drawbacks associated with the prior art combustion of fuel so as to approach a substantially “perfect combustion” in which such fuel (i.e., fuels containing hydrocarbons) and the air are substantially completely reacted with one another to result in substantially only carbon dioxide (CO₂) and water (H₂O) and unaffected nitrogen (NO₂).

An object of the present invention is to provide a burner which is relatively inexpensive to manufacture but which has an improved efficiency while still minimizing the generation of CO₂ during operation thereof.

A further object of the present invention is to atomize or vaporize substantially all of the fuel components and mix the vaporized fuel components with an adequate supply of air (e.g., oxygen) to thereby result in a complete and thorough combustion of all of the fuel components (i.e., hydrocarbons) so as to minimize the discharge of any pollutants (e.g., unburned hydrocarbons) which are exhausted to the atmosphere. Such complete combustion thereby increases the overall energy efficiency of the combustion system.

Yet another object of the present invention is to minimize the consumption of the fuel product, during combustion, and maximize utilization of the air to thereby result in a clean and more thorough combustion of the fuel components.

A still further object of the present invention is to combine two different fuels with one another, e.g., a gaseous fuel component such as compressed air, propane, natural gas, etc., and a liquid fuel component such as gasoline, kerosene, #2 home heating oil, diesel fuels such, as standard diesel fuel and bio-diesel, or some other petroleum or combustible product and form an atomized and/or a vaporized fuel mixture thereof which, when burned, results in the complete and thorough combustion of the atomized vaporized fuel mixture.

Yet another object of the invention is to provide a process and an apparatus in which the fuel component is emitted from the nozzle separately from the air component so that the fuel and air components only mix with one another immediately after entering the burner and thereby form a uniform combustion mixture which is substantially completely consumed upon combustion.

A still further object of the invention is to have the fuel component outlet centered with respect to air component outlet, and have the fuel component outlet extend a small distance further into the combustion boiler and have the air component assist with withdrawing and/or extracting the fuel component from the fuel component outlet and thereby form a uniform combustion mixture of minute particles which is substantially completely consumed upon combustion.

A further object of the present invention is to provide an improved burner, which comprises may conventional furnaces components but altering the manner in which the liquid fuel component and the pressurized air are discharged into the burner box to improve combustion thereof.

Still another object of the invention to provide a burner system in which the supplied fuel components are only atomized and intimately mixed with one another upon entering the burner box and facilitate substantially complete combustion of the fuel mixture.

A still further object of the present invention is to provide a pair of closely spaced discharged nozzles which are each supplied with a liquid fuel component and a pressurized air component so that the pair of discharged nozzles discharged the liquid fuel component and the pressurized air component directly into the burner box where the fuel components intimately mix with one another.

Yet another object of the present invention is to discharge the pressurized air component concentrically around the liquid fuel component so that the pressurized air component assists with withdrawing the liquid fuel component from the liquid fuel orifice and automatization of the liquid fuel component to a particle size of between about 30 microns and about 35 microns.

A further object of the present invention is to provide adequate control over the supply rate of the fuel component so as to minimize consumption of the liquid fuel component and also facilitates substantially complete combustion of the fuel mixture.

Still another object of the present invention, it to provide an air compressor for supplying the pressurized air component and equipping the air compressor with control features which control both the flow rate as well as the supply pressure of the compressed air and thereby facilitate the combustion of the fuel mixture.

Another object of the present invention is to supply a major portion of the supplemental air directly to the burner box while only diverting a small portion of the supplemental air and supplying the same to the discharged nozzles to facilitate cooling of the discharged nozzles and combustion of the fuel mixture.

The present invention also relates to a burner for burning a fuel mixture, the burner comprising: a pair of discharge nozzles each having a liquid fuel orifice and an air orifice located concentrically with the liquid fuel orifice; a liquid fuel conduit being coupled to the pair of discharge nozzles for supplying a liquid fuel component to each of the liquid fuel orifices; an air conduit being coupled to the pair of discharge nozzles for supplying an air component to each of the air orifices; a pressurized air source being connected with the air conduit for supplying the pressurized air component to the air conduit; the liquid fuel component being supplied to the pair of discharge nozzles completely separate from the pressurized air component so that the liquid fuel component only mixing with the pressurized air component to form the fuel mixture once the liquid fuel component and the pressurized air component are discharged from the respective orifices; a supplemental air fan for supplying supplement air to the pair of discharge nozzles to facilitate substantially complete combustion of the fuel mixture; and an igniter for igniting the fuel mixture following discharged from the pair of discharge nozzles.

The present invention also relates to a burner system for burning a fuel mixture, the burner system comprising: a pair of discharge nozzles each having a liquid fuel orifice and an air orifice located concentrically with the liquid fuel orifice; a liquid fuel conduit being coupled to the pair of discharge nozzles for supplying a liquid fuel to each of the liquid fuel orifices; an air conduit being coupled to the pair of discharge nozzles for supplying a pressurized air to each of the air orifices; a liquid fuel supply being coupled to the liquid fuel conduit for supplying the liquid fuel to liquid fuel conduit; a pressurized air source being connected with the air conduit for supplying the pressurized air to the air conduit; the liquid fuel being supplied to the pair of discharge nozzles completely separate from the pressurized air so that the liquid fuel only mixing with the pressurized air, to form the fuel mixture, once the liquid fuel and the pressurized air are discharged from the liquid fuel and pressurized air orifices; a supplemental air fan for supplying supplement air to the pair of discharge nozzles to facilitate substantially complete combustion of the fuel mixture; a blast tube surrounding the pair of discharge nozzles; an air deflector sleeve being accommodate within the blast tube, the air deflector being located concentric with the blast tube and separating the blast tube from at least the pair of discharge nozzles, and the air deflector sleeve being located so as to divert some of supplemental air, from the supplemental air fan, to flow toward the pair of discharge nozzles while channeling a remainder of the supplemental air to flow along the blast tube, between the air deflector and the blast tube, and be discharged directly into the burner box; a flame retention head being supported at an outlet end of the blast tube, a second end of the air deflector being connected to the flame retention head, and the air deflector sleeve prevents a majority of the supplemental air from flowing toward the pair of discharge nozzles; an igniter for igniting the fuel mixture following discharged from the pair of discharge nozzles; and a flame detector being located adjacent the pair of nozzles for detecting presence of a flame generated by combustion of the fuel mixture.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described, by way of example, with reference to the accompanying drawings in which:

FIG. 1 is a diagrammatic drawing showing the basic components for the improved fuel combustion system according to the present invention;

FIG. 2 is a diagrammatic drawing showing a mixing chamber of the fuel combustion system in greater detail;

FIG. 3 is a diagrammatic drawing of a second embodiment of the improved fuel combustion system according to the present invention;

FIG. 4 is a diagrammatic drawing of the second embodiment of the improved fuel combustion system incorporated into a heating system; and

FIG. 5 is a diagrammatic drawing of a single spray nozzle of the second embodiment of the improved fuel combustion system.

FIG. 6 is a block diagrammatic of a third embodiment of the improved fuel combustion system for use with a heating system;

FIG. 7 is a diagrammatic view of the third embodiment of the improved fuel combustion system showing further details thereof;

FIG. 8 is a diagrammatic wiring diagram of the third embodiment of the present invention;

FIG. 9 is a diagrammatic drawing showing mixing of the liquid and gas fuel sources with an ample supply of oxygen to facilitate complete combustion thereof;

FIG. 10 is a diagrammatic drawing showing the single discharge nozzle for adequately mixing the liquid fuel source with the compressed air to provide an atomized mixture thereof which can be substantially instantaneously burned;

FIG. 11 is a table showing the test results for a 30 year furnace, which was modified according to the present invention, to have an improved efficiency which still minimizing the generation of CO₂;

FIG. 12A is a diagrammatic view of another embodiment of the improved fuel combustion system showing details of the fan, motor and pressurized air source;

FIG. 12B is a diagrammatic view of showing the blast tube components of FIG. 12A;

FIG. 13A is a diagrammatic side perspective view of the internal burner components which are accommodated by the support plate within the blast tube;

FIG. 13B is a diagrammatic front perspective view of the internal burner components of FIG. 13A;

FIG. 14A is a diagrammatic side elevational view of a flame retention head which is supported by the leading end of the blast tube;

FIG. 14B is a diagrammatic front elevational view, of the flame retention of

FIG. 14A, shown affixed to the leading end of the blast tube;

FIG. 15A is a diagrammatic top plan view of a pair of discharge nozzles according the present invention;

FIG. 15B is a diagrammatic front elevational view of FIG. 15A;

FIG. 15C is a diagrammatic front elevational view of FIG. 15A;

FIG. 15D is a diagrammatic rear elevation view of FIG. 15A;

FIG. 16 is a diagrammatic cross sectional view along section line 16-16 of FIG. 15A;

FIG. 17 is a diagrammatic cross sectional showing the liquid and air discharge from one of the nozzles of FIG. 15A;

FIG. 18 is an enlarged view showing the separate fuel discharge and the pressurized air discharge from the respective orifices into the burner box for mixing with one another upon entering the burner;

FIG. 19 is a diagrammatic wiring diagram of an embodiment of the present invention;

FIG. 20 is a diagrammatic view showing the spray pattern for the pair of discharge nozzles of FIGS. 15A-15D; and

FIG. 21 is a diagrammatic view showing a further embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Turning now to FIGS. 1 and 2, a detailed description of the vapor fuel combustion system 2, according to the present invention, will now be described. As can be seen in these Figures, the vapor fuel combustion system 2 generally comprises a sealed mixing chamber 4. An outlet 6 of the mixing chamber 4 is coupled, via a first leg 8 of a vapor fuel supply conduit 10, to an inlet 12 of a vacuum pump 14. An outlet 16 of the vacuum pump 14 is coupled, via a second leg 18 of the vapor fuel supply conduit 10, to an inlet 20 of a conventional burner 22 which facilitates combustion, in a conventional manner, of the vaporized fuel supplied thereto. The burner 22 is typically located to heat a conventional furnace 24, in a normal fashion or manner, and the generated heat from the furnace 24 is disbursed throughout a building by a conventional heating system of the building 67 (not described in further detail). As both the furnace 24 and the heating system 68 are conventional and well know and as neither, per se, forms any part of the present invention, a further detailed description concerning the furnace or the heat system of the building will not be provided.

A liquid fuel component storage source 26 is provided for accommodating a desired quantity of a liquid petroleum fuel 28, e.g., 10-100 gallons, etc., of a petroleum product such as gasoline, kerosene, #2 home heating oil, diesel fuels such, as standard diesel fuel and bio-diesel, or some other petroleum or combustible product. A first end 30 of a liquid fuel supply conduit 32 communicates with and is located adjacent the bottom of the liquid fuel component storage source 26, while a second end 34 of the liquid fuel supply conduit 32 communicates with and is located adjacent the bottom or a lower region of the mixing chamber 4 to supply the desired quantity of the liquid fuel component 28 to the bottom of the mixing chamber 4 during operation of the vapor fuel combustion system 2. Typically, a quantity of the liquid fuel component 28 is allowed to accumulate in the bottom of the mixing chamber 4 and the level of liquid fuel component 28 which is allowed to accumulate may vary, depending upon the particular application and the characteristics of the mixing chamber 4. The inventors have found that a level of between about 3 inches or so is generally adequate, but other fuel levels could also be utilized and would be readily apparent, depending upon the specific application and heating requirements, to those skilled in the art.

The combustion system 2 also includes a gaseous fuel component storage source 36 which accommodates a desired quantity of the gaseous fuel component 38, e.g., propane, natural gas, etc. A first end 40 of a gaseous fuel supply conduit 42 is connected to the gaseous fuel component storage source 36 while a second end 44 of the gaseous fuel supply conduit 42 communicates with the mixing chamber 4. An outlet of the second end 44 of the gaseous fuel supply conduit 42 is located within the mixing chamber 4 so as to be submerged within the liquid fuel component 28 accommodated therein, e.g., be submerged by at least 1 inch or so. The gaseous fuel conduit 42 has a regulator valve 45 for completely interrupting and/or regulating the flow of gaseous fuel component 38 supplied from the gaseous fuel component storage source 36 to the liquid fuel component 28 contained within the mixing chamber 4. Typically the flow pressure of the gaseous fuel component 38 is about ⅛ pound of pressure or so. Such pressure is typically adequate to allow a sufficient flow of the gaseous fuel component 38 to the mixing chamber 4 for bubbling and permeating through the liquid fuel component 28 located within the mixing chamber 4 and thereby inducing some of the liquid fuel component 28 to become vaporized and mixed with the gaseous fuel component 38 and result in the formation of a substantially uniform mixture thereof. It will be appreciated, by those skilled in the art, that other supply pressures may be utilized depending upon the specific application and the heating requirements. Preferably the outlet of the second end 44 of the gaseous fuel supply conduit 42 has an enlarged outlet (not shown in detail) to facilitate supply of the gaseous fuel component throughout the liquid fuel component 28 accommodated within the mixing chamber 4.

In addition, the mixing chamber 4 is provided with one or more air intake inlet(s) 46 for allowing an adequate quantity of room air (e.g., oxygen) to flow or enter the mixing chamber 4 and mix with the vaporized liquid and the gaseous fuel components and thereby form a substantially uniform vaporized mixture thereof, e.g., form a vaporized fuel mixture 48. The air intake inlet 46 normally has a check valve 50 associated therewith to ensure that the room air is only allowed to enter the mixing chamber 4 when the vapor fuel combustion system 2 is operating, e.g., the vacuum pump 14 is operating and drawing from the mixing chamber 4 and supplying the vaporized fuel mixture to the burner 22 but not allow any of the vaporized fuel components to flow out through the air intake check valve(s) 50.

To assist with creation of a substantially uniform vaporized fuel mixture 48 of the vaporized liquid fuel component 28, the gaseous fuel component 38, and the air, a sparger/diffuser member 52 is located so as to separate the intake 6 of the first leg 8 of the vapor fuel supply conduit 10 from a remainder of the interior space of the mixing chamber 4. That is, the vaporized liquid and gaseous fuel components 28, 38 as well as the air must generally pass through one or more small opening or passages 54, formed in the sparger/diffuser member 52, prior to those components being sucked into the intake 6 of the first leg 8 of the vapor fuel supply conduit 10 and conveyed to the burner 22 for combustion.

The vacuum pump 14 is typically a piston pump which is capable of achieving about 30 pounds of suction at the intake 6 of the first leg 8 of the vapor fuel supply conduit 10 during operation. Preferably the first leg 8 of the vapor fuel supply conduit 10 has a larger diameter than the second leg 18 of the vapor fuel supply conduit 10 which supplies the vaporized fuel from the vacuum pump 14 to the burner 22. According to one embodiment, the first leg 8 of the vapor fuel supply conduit 10 has a diameter of about ⅜ of an inch or so while the second leg 18 of the vapor fuel supply conduit 10 has a diameter of about ¼ of an inch or so. It is to be appreciated that other sizes would be readily apparent to those skilled in the art without departing form the spirit and scope of the present invention.

Typically a water trap 56 is provided along either the first leg 8 and/or the second leg 18 of the vapor fuel supply conduits 10, or both legs, to facilitate removal of any liquid fuel 28 which may possibly condense while flowing along the vapor fuel supply conduit 10 from the mixing chamber 4 to the burner 22.

Preferably the intake 6 of the first leg 8 of the vapor fuel supply conduit 10 is located approximately 18 inches or so above the level of the liquid fuel component 28 contained within the mixing chamber 4. In addition, preferably a pair of air inlets 46 are provided in the mixing chamber 4 (e.g., one adjacent each side of the mixing chamber 4) to ensure that an adequate supply of air is allowed to enter into the mixing chamber 4 to mix with the gaseous and liquid vaporized fuel components 28, 38 and facilitate formation of vaporized fuel mixture which promotes substantially perfect combustion of the vaporized fuel mixture upon combustion.

Preferably the lower section of the mixing chamber 4 is provided with a high level and low level liquid fuel component sensors 58, 60 which are each connected to a flow valve 62 located along the liquid fuel supply conduit 32, to facilitate maintaining a desired level of the liquid fuel component 28 within the mixing chamber 4 during operation. When the low level sensor 60, for the liquid fuel component 28, determines that the level of the liquid fuel component 28 is below the low level sensor 60, a signal is sent to the flow valve 62 to open the valve 62 and allow the liquid fuel component 28 to flow from the liquid fuel component storage source 26 into the mixing chamber 4 and raise the level of the liquid fuel component 28 into the mixing chamber 4 until the high level sensor 58 detects the liquid fuel component 28. Thereafter, the high level sensor 58 sends a signal to the flow valve 62 to close the valve 62 and interrupt or discontinue further flow of liquid fuel component 28 into the mixing chamber 4. It is to be appreciated that other fluid level indicators and flow valve controllers would be readily apparent to those skilled in the art without departing form the spirit and scope of the present invention.

A heating system control unit 64 communicates with each of the gaseous fuel regulating valve 45, the vacuum pump 14, the burner 22 and a thermostat 66 via conventional electrical lines and/or connections 68. The thermostat 66 sends signals to the control unit 64 to either commence or terminate operation of the combustion system 2, depending on the current temperature detected by the thermostat 66 associated with the control unit 64. When the thermostat 66 indicates a low temperature within the building, the control unit 64 activates the combustion system 2 and also activates burner 22. The vacuum pump 14 will initiate operation and supply the burner 22 with the necessary quantity of vaporized fuel mixture 48. The control unit 64 will also open the gaseous fuel regulating valve 45 to commence the supply of the gaseous fuel 38 to the mixing chamber 4.

Operation of the vapor fuel combustion system 2 will now be described.

When the heating system 67 requires additional heat, as determined by the thermostat 66 or some other conventional devices, the control unit 64 opens the flow valve 45 for the gaseous fuel component 38 to allow the gaseous fuel component 38 to flow from the gaseous fuel component storage source 36 through the regulator valve 45 and into the mixing chamber 4. The gaseous fuel component 38 then permeates and bubbles through the liquid fuel component 28, contained in the bottom of the mixing chamber 4, to induce vaporization thereof. At the same time, the vacuum pump 14 commences operation to syphon and/or withdraw the vaporized fuel components, once adequately mixed with room air, from the mixing chamber 4 and supply the vaporized fuel mixture to the burner 22 for combustion via the vapor fuel supply conduit 10 and the vacuum pump 14. The evacuation of the vaporized fuel mixture 48 from the mixing chamber 4 causes a negative pressure within the mixing chamber 4. This negative pressure opens the check valve 50, associated with the air intake inlet 46, to allow additional atmospheric air to enter the mixing chamber 4.

After receiving a signal from the control unit 64, the burner 22 ignites the supply of vaporized fuel mixture, in a conventional fashion, and the combustion gases generate heat which is used to heat a conventional hot water heating system 67, for example, or a conventional forced hot air heating system, etc.

During operation, once a sufficient quantity of the liquid fuel 28 component becomes vaporized such that the low level sensor 60 detects an insufficient quantity of the liquid fuel component 28, additional liquid fuel component 28 is allowed to flow from the liquid fuel component storage source 26 into the mixing chamber 4.

Once the burner 22 generates sufficient heat to the furnace 24 and the associated heating system 67 and this heat is disbursed throughout the building, the thermostat 66 eventually detects an adequate increase in temperature within the building and indicates the same to the control unit 64. The control unit 64 then automatically shuts down the vapor fuel combustion system 2, e.g., turns or shuts off the burner 22 and the vacuum pump 14 and closes the regulator valve 45 supplying the gaseous fuel component 38 to the mixing chamber 4. This, in turn, allows the check valve 50 for the air intake(s) 46 to close automatically and seal and thereby prevent additional air from entering into the mixing chamber 4 and/or allow any of the vaporized fuel components, contained within the mixing chamber 4, to escape therefrom into the room or atmosphere.

Preferably the mixing chamber 4 is a completely sealed unit which has a storage capacity of between 5 and 300 cubic feet or so and more preferably has a storage capacity of between about 10 and 50 cubic feet.

The inventors of the present invention believe that by permeating the gaseous fuel component 38 through the liquid fuel component 28, such as by bubbling and permeation, this induces vaporization of the liquid fuel component 28 and thereby results in the formation of a composite vaporized fuel mixture 48 which minimizes the amount of any unburned hydrocarbons in the combustion byproducts and thereby facilitates extracting virtually all of the BTU energy from the composite vaporized fuel mixture during conventional combustion thereof. That is, the present invention is believed to approach substantially “perfect combustion” of the composite vaporized fuel mixture such that all of the fuel (e.g., hydrocarbons) is combined with a sufficient supply of air (e.g., oxygen and nitrogen) and, upon combustion thereof, generally results only in carbon dioxide and water, plus unaffected nitrogen, as the sole combustion byproducts.

It is to be appreciated that the present invention may be also useful in a commercial production facility for manufacture of a composite vaporized fuel mixture. That is, the commercial production facility will include a commercial gaseous fuel component source, a commercial liquid fuel component source, a commercial mixing chamber and one or more commercial vacuum pump(s). The vacuum pump(s) would supply the vaporized fuel mixture to an associated compressor for compressing the vaporized fuel mixture, at high pressure, and storing the same in suitable conventional pressurized containers, e.g., 20 lbs., 50 lbs., 100 lbs., 200 lbs., etc., pressurized containers. Each such pressurized container would thus already have the desire amount of vaporized fuel, from both fuel sources, as well as a desired amount of oxygen to facilitate direct supply of this fuel source to a burner without requiring the addition of any additional oxygen thereto prior to combustion.

Turning now to FIGS. 3 and 5, a detailed description concerning a second embodiment of the vapor fuel combustion system 2′, according to the present invention, will now be described in detail. As can be seen in these Figures, the second embodiment of the vapor fuel combustion system 2′ generally comprises a liquid fuel supply storage tank 72, e.g., approximately 10-300 gallons or so, of a petroleum product accommodating a desired quantity of a liquid fuel component 74 such as gasoline, #2 home heating oil, kerosene, standard diesel fuel, bio-diesel fuel or some other combustible fuel, for example. An adjustable flow valve 76, typically located adjacent the bottom of the fuel supply storage tank 72 or in a liquid fuel supply conduit 78 coupled thereto, regulates the flow rate of the liquid fuel which is allowed to flow from the fuel supply storage tank 72 to the combustion system 2′. The flow valve 76 can be either a manually adjustable or controllable flow valve or, more preferably, an automatically adjustable or controllable flow valve which is coupled to a control system C (see FIG. 5) for controlling the flow of liquid fuel from the liquid fuel supply storage tank 72. As the adjustable or controllable flow valve 76 is conventional and well known, a further detailed description concerning such valve will not be provided. The liquid fuel supply conduit 78 is coupled to either the adjustable or controllable flow valve 76 or the liquid fuel supply storage tank 72 for supplying the fuel from the fuel supply storage tank 72 to an liquid fuel (first) inlet 80 of a pressured spray nozzle 82.

A compressor or a pressurized gas source 84, e.g., air, oxygen, etc., is coupled to a pressurized gas (second) inlet 86 of the pressure spray nozzle 82 via a pressurized gas supply conduit 88. A gas pressure valve 90 is provided either at the compressor or the pressurized gas source 84 or along the pressurized gas supply conduit 88 for adjusting the pressure and the flow rate of the gas as the gas flows along the conduit 88. The gas pressure valve 90 typically adjusts the gas pressure such that the mixing chamber is maintained at a pressure of, for example, between about 3 and 8 psi. The pressurized gas is introduced into the spray nozzle 82, via the pressurized gas (second) inlet 86 located adjacent a rear of the spray nozzle 82, while the liquid fuel is introduced into the spray nozzle 82, via the liquid fuel (first) inlet 80 also located adjacent the rear of the spray nozzle 82. It is to be appreciated that the location of the first and the second inlets 80, 86 could vary. The fuel supplied via the pressurized gas (second) inlet 86 and the liquid fuel inlet 80 both communicate with one another in an internal mixing chamber 94 within the spray nozzle 82. The liquid fuel and the pressurized gas mix with one another, at an elevated pressure, within the mixing chamber 94 to form a composite fuel mixture, and this fuel mixture is then accelerated as the fuel mixture is discharged out via the relatively small discharge opening 96 of the spray nozzle 82, e.g., an opening of between about 0.01 and 0.05 inches or so. Due to the relatively high pressure of the mixing chamber 94 and the relatively small size of the discharge opening 96 of the spray nozzle 82, the mixture is essentially atomized substantially immediately upon being discharged from the spray nozzle 82. That is, the discharge opening 96 of the spray nozzle 82 and the pressure difference between the pressure of the internal mixing chamber 94 and the atmospheric pressure located downstream of the spray nozzle 82 are such that sufficiently all of the liquid fuel becomes instantaneously atomized so as to be immediate suitable for combustion.

A conventional igniter 98 is located downstream but sufficiently close to the discharge opening 96 of the spray nozzle 82 to facilitate ignition of the fuel mixture being discharged and atomized by the spray nozzle 82. To facilitate substantially complete combustion of the fuel mixture, the supplemental air is forced into a first end 102 of a burner housing 100, and this supplemental air is initially heated as this air passes through a burn zone—the burn zone 104 is an area within the flame shroud 110 where the atomized liquid fuel is ignited by the igniter 98 of the ignition system. The ignition system includes the ignitor 98 arranged along the axis of the vapor fuel combustion system 2′, downstream from the spray nozzle 82, so that as the atomized liquid fuel mixture is sprayed into the flowing stream of supplemental air, the ignitor 98 is energized and thus ignites the atomized liquid fuel mixture. The ignitor 98 may include a pilot flame, an electrical spark, a glowing resistor, etc., and communicates with an ignition control system 107 which energizes or interrupts the flow of electrical power, for example, to the ignitor 98 as necessary. As the igniter 98 and a remainder of the ignition control system 107 are conventional and well known in the art, a further detailed description concerning the same is not provided.

The flame shroud 110 is accommodated within the burner housing 100 and is generally in the form of a cylindrical tube which has a diameter of between 2 and 12 inches. The flame shroud 110 surrounds and encases the spray nozzle 82. The spray nozzle 82 is arranged within the elongate burner housing 100 so as to discharge the fuel along a central axis of the vapor fuel combustion system 2′. It is to be appreciated that the overall size, shape and configuration of the burner housing 100 and the flame shroud 110 may vary, depending upon the particular application, but is generally designed so as to induce sufficient air flow from the open first end 102, of the flame shroud 110, to an opposed second open end 106 thereof. The first end 102 of the housing is generally open so as to allow an inward flow of supplemental air, into the flame shroud 110, and thereby ensure substantially complete combustion of all of the supplied fuel. To assist with air flowing through the flame shroud 110, a fan or blower 108, for example, may be provided to drawing or forcing supplemental air into the first open end 102 of the flame shroud 110 and channeling or directing such air therethrough toward the second open end 106 thereof. Preferably a speed of the fan or the blower 108 is adjustable in order to regulate the velocity of the supplemental air being forced or directed through the burner housing 100, e.g., at a flow rate of between 5 feet per second to about 100 feet per second or so, for example. The flame shroud 110 restricts the combustion of the fuel mixture along the axis of the vapor fuel combustion system 2′ so as prevent the burner housing 100 from becoming excessively hot during the combustion process.

The vapor fuel combustion system 2′, of the second embodiment, allows adjustment of the fuel flow rate to the spray nozzle 82, adjustment of the pressurized gas flow rate to the spray nozzle 82 and the amount and the velocity of the supplemental air allowed to mix with the sprayed fuel mixture, within the burner housing 100, to ensure a substantially complete combustion of all of the sprayed fuel mixture. As the flow rate of the liquid fuel decreases, the amount of supplemental air forced through the combustion system 2′ is generally correspondingly decreased. As the flow rate of the liquid fuel increases, the amount of supplemental air forced through the combustion system 2′ will also generally correspondingly increase. As the flow of pressurized gas increases or decreases, the difference in pressure between the mixing chamber 94 and the atmosphere outside of the spray nozzle 82 changes thus altering the burning efficiency of the liquid fuel.

The vapor fuel combustion system 2′, according to the present invention, may be incorporated into an individual space heater or used as a burner or a heat source for a conventional furnace of a heating system, as diagrammatically shown in FIG. 4. The heating system used with the vapor fuel combustion system would be similar to any known heating system having a heating chamber with a water heating coil, a water inlet and a water outlet.

Turning now to FIGS. 6-10, a detailed description concerning a third embodiment of the fuel combustion system 2″, according to the present invention, somewhat similar to the second embodiment will now be described in detail. As can be seen in FIGS. 6-8, the fuel combustion system 2″ generally comprises a liquid fuel supply storage tank 72, e.g., having a storage capacity of approximately 10 to a 300 gallons or more, for example, for storing a petroleum product such as No. 2 home heating oil, kerosene, diesel fuel, bio-diesel fuel or some other combustible fuel. A liquid fuel pump 112 is coupled to the liquid fuel supply storage tank 72, via a first section of a liquid fuel supply conduit 114, for pumping the liquid fuel from the liquid fuel supply storage tank 72 to a burner 122 for combustion. A further section of a liquid fuel supply conduit 114 couples the liquid fuel pump 112 to a liquid fuel reservoir 116 for supplying the liquid fuel thereto. Typically either the liquid fuel conduit 114 or the liquid fuel reservoir 116 is provided with a conventional hydronic air vent 118 which allow the liquid fuel reservoir 116 to breath, e.g., facilitates the replenishment or the addition of air thereto, as the liquid fuel is removed therefrom during operation of the combustion system 2′. As shown in FIGS. 7 and 8, the hydronic air vent 118 is shown coupled to the liquid fuel conduit 114 but other arrangements are also within the spirit and scope of this invention.

The liquid fuel reservoir 116 typically holds between 8 ounces and 128 ounces of liquid fuel therein and, as discussed below in further detail, is generally a gravity feed reservoir which operates at a very slight positive pressure, e.g., a positive pressure of between approximately 1-35 inches of water (e.g., generally less than 1⅓ PSI). Typically, the liquid fuel reservoir 116 is equipped, adjacent a vertically uppermost portion thereof, with a float valve 126 which is coupled to a float switch 128. The float switch 128 controls operation of the liquid fuel pump 112 to facilitate turning the liquid fuel pump 112 “on” and “off' so that the liquid fuel pump 112 may be automatically controlled and operated to supply, as necessary, the liquid fuel from the liquid fuel storage tank 72 to the liquid fuel reservoir 116 during operation of the combustion system 2″.

An outlet of the liquid fuel reservoir 116 is coupled, via a third section of the liquid fuel supply conduit 114, to a liquid fuel inlet 120 of a discharge nozzle 124. A solenoid valve 130, e.g., an solenoid valve manufactured by ASCO Red-Hat Valves of N. Cuthbert Inc. of Toledo, Ohio or Automatic Switch, Co., is provided along the third section of the liquid fuel supply conduit and this valve, when the solenoid valve 130 is activated or open, allows the flow of the liquid fuel from the liquid fuel reservoir 116 to the discharge nozzle 124 and, when the solenoid valve 130 is deactivated or closed, interrupts the flow of the liquid fuel from the liquid fuel reservoir 116 to the discharge nozzle 124. A further detailed discussion concerning the supply, mixing, discharge and combustion of the liquid fuel will follow below.

An air compressor 132, e.g., an oil-less air compressor, is coupled, via an air supply conduit 134, to a compressed air inlet 136 of the discharge nozzle 124 for supplying compressed air thereto. The air supply conduit 134 typically includes an air pressure gauge 138 for detecting and displaying the pressure of the compressed air being supplied by the air compressor 132 to the discharge nozzle 124. The compressed air is typically supplied to the discharge nozzle 124, via the air compressor 132, at an air pressure of between 2 and 30 psi and more preferably supplied at an air pressure of about 20 psi or less, or preferably at a pressure between about 4 psi and 8 psi. A further detail discussion concerning mixing of the compressed air with the liquid fuel and combustion of that formed fuel mixture 153 will follow below. The fuel is typically operated at a pressure of between 0.25 psi and about 2 psi and more preferably at a fuel pressure of 0.5 psi.

The discharge nozzle 124 is typically located within and enclosed by a cylindrical blast tube or housing 140. The blast tube or housing 140 typically has a diameter of between 4 and 6 inches and a length of between 4 and 24 inches with the discharge orifice 125 of the discharge nozzle 124 being located closely adjacent a leading first outlet end of the blast tube or housing 140. A blast tube fan 142 is located behind and upstream of the discharge nozzle 124, adjacent an inlet end of the blast tube or housing 140, for supplying additional combustion air to the liquid fuel/compressed air fuel mixture 153 being atomized and exhausted from the discharge orifice 125 of the discharge nozzle 124 during operation of the combustion system 2″. This additional combustion air, along with the compressed air supplied by the air compressor 132, facilitates substantially complete combustion of all of the liquid fuel as the liquid fuel/compressed air mixture ignites, burns and is consumed within the furnace 154. The blast tube fan 142 typically supplies between 10 and 120 cubic feet per minute or so of additional combustion air and more preferably supplies about 80 cubic feet per minute or so of additional combustion air. Preferably the rotational speed of the blast tube fan 142 is variable or adjustable so as to allow adjustment of the rotational speed of the fan blades 144 and thereby the amount of additional air which is supplied to and mixes with the liquid fuel/compressed air mixture discharged by the discharge nozzle 124 into the furnace 154 to thereby result optimal and substantially complete combustion of all of the liquid fuel during operation of the combustion system 2″.

The discharge nozzle 124 generally comprises (see FIGS. 9 and 10) a pair of concentric nozzle openings, i.e., a centrally located internal nozzle 146 and a centrally located exterior nozzle or discharge orifice 125 formed in a cover 127 of the discharge nozzle 124. The liquid fuel is supplied to and discharged via the internal centrally located nozzle 146 and an internal needle valve 148 cooperates with the internal nozzle 146 to facilitate adjustment of the flow rate of the liquid fuel therethrough during operation of the combustion system 2″. Rotation of the internal needle valve 148 in a first rotational direction decreases the cross-sectional flow area, between an exterior surface of the needle valve 148 and the inwardly facing surface of the internal nozzle 146, to thereby restrict the flow rate of the liquid fuel that is permitted to pass therethrough and be exhausted by the liquid fuel nozzle 146, while rotation of the internal needle valve 148, in the opposite direction, increases the cross-sectional area, between an exterior surface of the needle valve and the inwardly facing surface of the internal nozzle 146, and thereby increases the flow rate of the liquid fuel that is permitted to pass therethrough. As it is desirable to minimize the amount of liquid fuel being consumed, preferably the nozzle is adjusted toward a minimal liquid fuel flow position so that the smallest amount of liquid fuel, e.g., between 2 and 40 ounces of liquid fuel per hour, for example, may pass through the liquid fuel inlet and be discharged by the internal nozzle 146 but the flow rate is adjusted by an operator to achieve optimum utilization of the liquid fuel.

A compressed air chamber 150, has a relatively small size of only about one to three cubic inches or less, is formed within the discharge valve 124, between an inwardly facing surface of cover 127 and an exterior surface of the internal nozzle 146, and this chamber generally encloses or encases an outlet of the internal valve 146 so that the liquid fuel is initially exhausted solely and directly into the compressed air chamber 150 for mixing with the compressed air. The exterior nozzle or discharge orifice 125 is typically concentric with but spaced from the internal nozzle 146 to provide sufficient area for the liquid fuel to mix with the compressed air, within the compressed air chamber 150, prior to the combined liquid fuel and compressed air fuel mixture 153 being accelerated and discharged, via the exterior nozzle or discharge orifice 125, into the furnace 154.

A compressed air valve 151 cooperates with an associated needle valve 152 to control the flow of the compressed air which is allowed to flow into the compressed air chamber and the needle valve 152 allows fine tuning adjustment of the compressed air flow into and through the compressed air chamber 150 for mixing with the liquid fuel and forming a liquid fuel/compress air fuel mixture 153 which is then discharged, via the exterior nozzle or discharge orifice 125 of the discharge nozzle 124, into a combustion zone of the furnace 154. Rotation of the compressed air needle valve 152, in a first rotational direction, decreases the cross-sectional flow area, between an exterior surface of the compressed air needle valve 152 and the inwardly facing surface of the compressed air nozzle 151, and thereby restricts the flow rate of the compressed air that is allowed to flow into the compressed air chamber 150 and mix with the liquid fuel and be discharged by the exterior nozzle or discharge orifice 125, while rotation of the compressed air needle valve 152, in the opposite direction, increases the cross-sectional flow area, between an exterior surface of the compressed air needle valve 152 and the inwardly facing surface of the compressed air nozzle 151, and thereby increases the flow rate of the compressed air that is permitted to flow into the compressed air chamber 150 and mix with the liquid fuel and be discharged by the exterior nozzle or discharge orifice 125.

Preferably both the liquid fuel needle valve 148 and the compressed air needle valve 152 each have a very fine thread to allow minute, fine adjustment of the flow of the liquid fuel and the compressed air, respectively, so that an optimized flame, e.g., the blue flame, can be achieved within the furnace as the fuel mixture 153 is consumed during operation of the combustion system 2″.

As the compressed air flows into through the compressed air chamber 150, the compressed air flows around and/or over the internal valve 146, the compressed air tends to create a vacuum which withdraws, sucks and/or evacuates the liquid fuel through the orifice of the internal nozzle 146. The slight positive pressure of the liquid fuel assists with the discharging of the liquid fuel from the internal nozzle 146. As the compressed air is under pressure, e.g., 2-30 psi for example, the compressed air along with the liquid fuel evacuated from the internal nozzle 146 normally swirls and adequately mixes with the withdrawn liquid fuel and the resulting fuel mixture is then discharged out through the discharge orifice 125 in a substantially atomized form, e.g., following discharge the liquid fuel typically has a droplet or particle size of between 5 and 15 microns, for example. Due to such fine liquid fuel particle size and due to the fact that the liquid fuel is adequately mixed with an ample supply of oxygen contained within the compressed air, substantially all of the liquid fuel is immediately burned and consumed upon being discharged from the spray nozzle 124 and burned within the furnace 154.

To assist further with such combustion, the blast tube fan 142 supplies additional air which facilitates substantially complete combustion of the liquid fuel. The blast tube fan 142 also controls the axial and radial dimensions of the flame burning within the furnace 154 as well as the spacing of the flame from the discharge nozzle 124. The exterior nozzle or discharge orifice 125 typically has about 0.4 mm diameter opening therein while the interior nozzle 146 typically has a 0.2-4 mm diameter opening therein, e.g., both nozzles have a diameter of between 0.01 and 0.8 millimeters.

To facilitate ignition of the fuel mixture 153, the combustion system 2″ is provided with a pair of conventional electrodes 156, 158 (see FIG. 7) which each have a tip located closely adjacent the discharge orifice 125 of the discharge nozzle 124, e.g., approximately ¼ of an inch to an 1 inch or so in front of the discharge orifice 125 with the electrode tips being spaced apart from one another by about ¼ of an inch to about ½ of an inch or so. In addition, a flame detector 160 is normally positioned upstream of the electrodes 156, 158 and located for viewing and detecting the presence of a flame, in the area immediately in front of the discharge orifice 125, to confirm whether or not a flame is present within the furnace 154. In the event that the flame detector 160 does not detect a flame, a lack of flame signal is then supplied, in a conventional manner, to the control unit 64 which then interrupts the flow of liquid fuel and/or compressed air to the discharge nozzle 124 and again initiates ignition of the flame, in a conventional manner. However, in the event that the flame detector 160 does, in fact, detect the presence of a flame resulting from the combustion of the fuel mixture 153, then such information is also conveyed to the control unit 64 which allows the burner to continue to operate and generate heat until a sufficient amount of heat is generated within the furnace 154 as detected by a thermostat 162, for example, located at a suitable location within the building to be heated.

The liquid fuel reservoir 116 is typically located vertically above the discharge orifice 125 of the discharge nozzle 124 so that liquid fuel, contained in the liquid fuel reservoir 116, creates a head of liquid (distance D in FIG. 8) which provides a slight positive pressure which causes the liquid fuel, within the liquid fuel reservoir 116, to flow from the liquid fuel reservoir 116 toward the liquid fuel inlet 120 of the discharge nozzle 124 when solenoid valve 130 is open. Typically the liquid fuel reservoir 116 is installed so that a distance or spacing D of the liquid fuel, i.e., a top surface of the liquid fuel contained within the liquid fuel reservoir 116, is between about 0.1 and about 35 inches above a height of the discharge orifice 125 of the discharge nozzle 124 of the spray device, more preferably the spacing D is about 2 to 10 inches, and most preferably the spacing D is about 3 inches or so. It is to be appreciated that the actual positive dispensing pressure of the liquid fuel, from the liquid fuel reservoir 116, will depend upon the relative vertical spacing or distance between the top surface or level of the liquid fuel, contained within the liquid fuel reservoir 116, and the discharge orifice 125 of the discharge nozzle 124.

As can be seen in FIG. 9, the cylindrical blast tube or housing 140 is equipped with an exterior adjustable flange 166, slidable and adjustably mounted on an exterior surface thereof, to facilitate attaching the nozzle end of the burner to a burner opening of a conventional boiler or furnace 154. Preferably the flange 166 is slidably adjustable along the exterior surface of the housing 140, in a conventional manner, to facilitate adjustment of the distance or the extent to which the leading or discharge end of the burner is allowed to project into a combustion chamber of the furnace 154 so that the burner flame is optimally located and positioned within the furnace 154 for generating a maximum amount of heat while, at the same time, consuming a minimal amount of liquid fuel.

As can be seen in FIG. 10, the liquid fuel is generally supplied along the central axis of the discharge nozzle and the liquid fuel needle valve can be minutely adjusted to vary the flow of liquid fuel which is allowed to be fed, via gravity, and at very slight positive pressure through the liquid fuel discharge opening. The compressed air generally enters the discharge nozzle circumferentially about the liquid fuel discharge nozzle 146 and the compressed air, along with the evacuated and/or sucked liquid fuel, are then mixed with one another and are constricted and accelerated as that fuel mixture 153 is discharged out through the discharge orifice 125 of the discharge nozzle 124. As a result of this, the liquid fuel 153 is substantially vaporized and/or atomized, upon being discharge therefrom, is thus immediately able to be rapidly consumed and burned within the furnace 154 while still minimizing consumption of fuel and maximizing the generation of heat within the furnace 154.

As is conventional in the art, it is desirable that the exhaust fumes, as such fumes are exhausted from the furnace 154 and flow up the chimney, typically have a temperature of at least 350° F. and, most preferably, have a temperature approaching 450° F., but typically no greater than 450° F. By adequately adjusting the supply pressure and/or the flow rate of the liquid fuel, the supply pressure and/or flow rate of the combustion air and/or the rotational speed of the blast tube fan 142, an operator is readily able to modify, adjust and/or alter the burner characteristics so as to achieve substantially complete combustion of the liquid fuel and thereby achieve exhaust fumes from the furnace 154 which have a temperature approaching, but typically no greater than, 450° F.

The third embodiment of the combustion system 2″ operates as follows.

When a building or other structure or facilitate requires heat, the thermostat 162 is triggered or activated and the send a control signal to control unit 62 which activates the air compressor 132 to commence supplying compressed air to the discharge nozzle 124. In addition, the solenoid valve 130 is also simultaneously actuated or opened to thereby allow the flow of the liquid fuel therethrough from the liquid fuel reservoir 116 to the liquid fuel discharge nozzle 146. Further, the blast tube fan 142 is turned on so as to supply additional combustion air to the burner. The pair of conventional electrodes 156, 158 are also activated, in a conventional manner by a conventional electronic fuel igniter 157, for igniting the fuel mixture 153 as this mixture discharges from the discharge orifice 125 of the discharge nozzle 124. Assuming that a flame is detected by the flame detector 160, the air compressor 132, the solenoid valve 130 and the blast tube fan 142 will all remain in an active, operating state until the combustion system 2″ eventually determines, in a conventional manner, that sufficient heat has been generated by the combustion system 2″ for the building or other structure requiring heat. Once this occurs, the control unit 62 will shut off the air compressor 132, which interrupts the supply of compressed air to the discharge nozzle 124, and also close the solenoid valve 130, which interrupts the flow of liquid fuel to the discharge nozzle 124, and discontinue the supply of electricity to the blast tube fan 142 to thereby terminate combustion of the fuel mixture 153 within the furnace 154. It is to be appreciated that the control unit 62 may be programmed to allow the blast tube fan 142 to continue to operate for a short duration of time, e.g., 10 seconds to a few minutes or so, after the flame is discontinued to facilitate purging of any remaining and/or unconsumed fuel mixture 153 still remaining within the burner or the furnace 154.

As with the previous embodiments, combustion of the fuel mixture 153, within the furnace, generates sufficient heat therein and this heat is, in turn, transferred to the associated heating system of the building or other structure, in a conventional manner, which then circulates and distributes the heat in a conventional manner throughout the building or other structure to be heated. The transfer medium, e.g., water, is then returned to the furnace 154 to be reheated for further redistribution of such heat via the associated heating system. Once the building or other structure is sufficient heated, the control unit 64 automatically shuts down the fuel combustion system 2″ which, in turn, shuts or turns off the solenoid valve 130, the air compressor 132, and the blast tube fan 142.

With reference to FIG. 11, the test results for a 30 year old burner, which was modified to incorporate the teaching of the present invention, are shown. As can be seen in this Figure, the modified burner has an efficiency ranging between 86.3 and 88.4% while only generating between 9.2 and 11.0% of CO₂ during operation. The inventors have found that the burner, incorporating the teachings of the present invention, results in an improved efficiency which is substantially equal to or better than most burners costing 3 to 5 times as much while, at the same time, typically generates less CO₂ than such more expensive burners. In addition, the burner, according to the teachings of the present invention, also generally results in a substantial savings in fuel costs by utilizing less fuel.

The spray nozzle 124 is preferably a Binks Model 460 automatic spray nozzle (manufactured Binks Manufacturing Company, Franklin Park, II and distributed by ITW Industrial Finishing of Glendale Heights, Ill.) which is conventionally used to atomize and spray paint for painting of a surface. The inventors have determined that an automatic spray nozzle, which sufficiently mixes the liquid fuel with an ample supply of oxygen from a combustion source, such as compressed air, and also atomizes the liquid fuel, upon being discharged from the nozzle, is sufficient for use with the present invention.

As can be seen in FIG. 8, the fuel combustion system 2″ further includes the power distribution unit for supplying electrical power to all of the various components contained and comprising the fuel combustion system 2″. The electrical power is supplied via input connection 170 and grounded via connection 172. An electrical box 174 is generally centrally located to facilitate electrical connection to the various components of the combustion system 2″. The various components of the combustion system 2″ are wired, as shown in FIG. 7 and briefly described below, as such wiring is standard and conventional in the art, a further detail description concerning the same is not provided.

BRIEF DESCRIPTION OF FIG. 8 WIRING

Line 225 From Hot Line to Float Switch

Line 226 From Drive Motor for Fuel Pump Burner to Float Switch

Line 227 From Electromechanical Thermostat to Fuel Primary

Line 228 From Electromechanical Thermostat to Fuel Primary

Line 229 From Drive Motor for Fuel Pump Burner to Ground

Line 230 From Drive Motor for Fuel Pump Burner to Neutral Line

Line 231 From Fuel Primary to Flame Detector

Line 232 From Fuel Primary to Hot Line

Line 233 From Fuel Primary to Neutral Line

Line 234 From Fuel Primary to Power Supply

Line 235 From Power Supply to Ground

Line 236 From Power Supply to Neutral Line

Line 237 From Asco Solenoid to Neutral Line

Line 238 From Asco Solenoid to Hot Line

Line 239 From Fan to Ground

Line 240 From Fan to Neutral Line

Line 241 From Duct Fan to Hot Line

Line 242 From Electronic Fuel Ignitor to Electrodes

Line 243 From Electronic Fuel Ignitor to Hot Line

Line 244 From Electronic Fuel Ignitor to Neutral Line

Line 245 From Air Compressor to Hot Line

Line 246 From Air Compressor to Ground

Line 247 From Air Compressor to Neutral Line

Turning now to FIGS. 12A-20, a description concerning a fourth embodiment of the fuel combustion system, according to the present invention, will now be described in detail. As this embodiment is somewhat similar to the previously described embodiments, only the differences between this embodiment and those previously described will now be described in detail.

According to this embodiment, the fuel discharge nozzle 200 comprises a pair of spaced apart discharge nozzles 202 which are arranged closely adjacent one another and supported by the same nozzle housing 204, see FIGS. 12B, 14B and 15A-15D, for example. Each one of the pair of discharge nozzles 202 is designed to discharge a liquid fuel component concentrically with respect to and surrounded by a pressurized air component directly into the burner box 206 for intimate mixing with one another and formation of a fuel mixture for substantially complete consumption within the burner box 206, and a further detail description concerning the features of the discharge nozzles 202 will be provided below.

As shown in FIG. 12A, liquid fuel is stored within a liquid fuel storage tank 72 and an inlet to the liquid fuel pump 112 is coupled to the liquid fuel storage tank 72, via a first section of the fuel supply conduit 114, for pumping the liquid fuel therefrom to the pair of discharge nozzles 202. A fuel solenoid valve 208 is located along this section of the fuel supply conduit 114, generally adjacent the inlet 210 to the liquid fuel pump 112, for interrupting the flow of liquid fuel to the fuel pump 112. The fuel solenoid valve 208 is coupled to the burner control system 212, in conventional manner, for opening the fuel solenoid valve 208 when the burner system is operating and closing the fuel solenoid valve 208 when the burner system shuts down. The outlet 214 of the fuel pump 112 is connected to a circulating section of the fuel supply conduit 114 while an opposite end of the circulating section of the fuel supply conduit 114 connects back to the fuel supply conduit 114 adjacent the connection of the fuel supply conduit 114 with the inlet 210 to the fuel pump 112. The circulating section of the fuel supply conduit 114 assists with circulating a majority of the pumped fuel back into the inlet 210 of the fuel pump 112.

A fuel supply section of the fuel supply conduit 114 is connected with the circulating section of the fuel supply conduit 114 for only removing a small portion of the circulated liquid fuel and supplying this removed portion, along a remainder of the liquid fuel supply conduit 114 into the nozzle housing 204 and to the respective liquid fuel discharge orifices 215 of the fuel discharge nozzles 202 for discharge into the burner box 206. A fuel restrictor 216 (see FIG. 12B) is located within the fuel supply section of the fuel supply conduit 114 for reducing the supply pressure of the liquid fuel pumped by the fuel pump 112 to the discharge nozzles 202. The fuel restrictor 216 typically has an opening therein of between 0.0015 and 0.0030 of an inch, and this opening allows the pressurized liquid fuel to flow from the fuel pump 112 toward the pair of discharge nozzles 202 while reducing the pressure of the pressurized liquid fuel being supplied. The fuel pump 112 typically supplies pressurized liquid fuel at a pressure of between 70 and 300 psi, for example, while the pressure of the supplied liquid fuel, after passing through the fuel restrictor 216, is typically reduced to a pressure of between about 0.5 psi and 2.0 psi, more preferably to a pressure of about 1.5 psi. It is to be appreciated that the liquid fuel pressure can vary and generally depends upon the overall burner system requirements. In order to facilitate fine turning of the flame characteristics, the fuel restrictor 216 is also readily changeable so that another fuel restrictor 216, having either a slightly larger or a slightly smaller opening therein, may be installed within the fuel supply line 114 so as to alter the pressure and/or flow rate of the liquid fuel supplied to the pair of discharge nozzles 202 and thus the characteristics of the flame BF in the burner box 206.

Preferably a 10 micron fuel filter 218, which only permits particles that are smaller than 10 microns in size to flow therethrough, is also located along the fuel supply conduit 114 to prevent large particles from flowing therealong and potentially clogging or otherwise obstructing the fuel discharge orifices 215 of either the discharge nozzles 202. Preferable the fuel filter 218 is locate upstream of the fuel restrictor 216 so as to filter out small particulate matter, from the liquid fuel supply, before the same can flow into the fuel restrictor 216 and obstruct and/or clog such restrictor.

Preferably the fuel pump 112 is a low flow rate fuel pump which typically pumps between about 1 gallon per minute to about 4 gallons per minute at a pressure of between about 70 psi and about 300 psi, for example. As a result of this fuel supply arrangement, a majority of the fuel, which is pumped by the fuel pump 112, is merely recirculated by the fuel pump 112 while only a minor portion of the fuel is actually supplied to the pair of fuel discharge nozzles 202.

As with the previous embodiments, the pressurized air is generally supplied by an air compressor or some other pressurized air source 220. The compressed air is supplied by a pressurized air supply 134 toward the pair of discharge nozzles 202. A pressurized air solenoid valve 222 is located along the pressurized air supply conduit 134 for interrupting the flow of the pressurized or compressed air to the pair of discharge nozzles 202, when the burner system is inactive. The pressurized air solenoid valve 222 is coupled to a burner control system 212, in conventional manner, for opening the pressurized air solenoid valve 222 when the burner system is operating and closing the pressurized air solenoid valve 222 when the burner system shuts down. Typically, the air compressor 220 will supply compressed air at the pressure of about 3-15 psi, and more preferably at a pressure of about 6 psi±2 psi and at a flow rate at between 1 and 1.5 cubic feet per minute. It is to be appreciated that for commercial embodiments, the flow rate of the compressed air may be somewhat higher, e.g., at a flow rate of about 3 cubic feet per minute, and the pressure of the supplied air may be also be somewhat higher as well.

Preferably, the air compressor 220 has a pair of adjustment controls, e.g., a first adjustment control 223 for adjusting the flow rate of the compressed air being supplied by the air compressor and a second adjustment control 224 for adjusting the pressure of the supplied compressed air. In addition, a replaceable air flow restrictor 248 is typically provided along the air supply conduit 134, between the air compressor 220 and the pair of discharge nozzles 202, to further assist with fine tuning the flow rate and the pressure of the pressurized or compressed air actually being supplied to the pressurized air discharge orifice 217. The air restrictor 248 typically has an opening therein of between 0.0020 and 0.0040 of an inch, and this opening allows the compressed air to flow from the air compressor toward the pair of discharge nozzles 202 while reducing the pressure of the compressed air being supplied. In order to facilitate fine turning of the flame characteristics, the air restrictor 248 is readily changeable so that another air restrictor 248, either having a slightly larger or a slightly smaller opening therein, may be installed within the compressed air line 134 so as to alter the characteristics of the air supplied to the pair of discharge nozzles 202 and thus the characteristics of the flame in the burner box 206. If desired, an air filter (not shown) is locate upstream of the air restrictor 248 so as to filter out small particulate matter from the compressed air source before the same can flow into the air restrictor 248 and obstruct and/or clog such restrictor.

As discussed herein, the pressurized or compressed air assists with sucking and/or withdrawing the liquid fuel from the fuel orifice 215 and atomizing the fuel into a particle size of between about 30 and about 35 microns±5 microns. The pressurized or compressed air also facilitates mixing of the two components with one another to from a desired fuel mixture for combustion. The inventors have determined that if the liquid fuel has a particle size significantly greater than about 35 microns, e.g., above 50 microns, then some of the liquid fuel particles are not completely burnt and/or consumed and such unburnt particles are exhausted up the flue. In addition, the inventors have found that if the liquid fuel particle size is significantly smaller than about 30, e.g., below 20 microns, then it is somewhat difficult to sustain continuous combustion of the fuel mixture and a portion of the fuel mixture is exhausted up the flue without ever being burnt and/or consumed within the burner box 206.

As is conventional in the prior art, a supplemental air fan 142, e.g., a squirrel cage type fan, is provided for supplying additional air to the burner box 206 and to the pair of discharge nozzles 202 to aid with combustion. An electric motor 250 typically drives or rotates the squirrel cage 251 of the supplemental air fan 142 at a desired rotational speed and in a desired direction. It is to be appreciated that the rotational speed of the supplemental air fan 142 can be varied, as desired in a conventional manner, for varying the flow rate of the supplemental air supplied to the pair of discharge nozzles 202 which assists with complete combustion of the fuel mixture. In addition, as is conventional in the prior art, a size of air inlet(s) for the supplemental air fan 142 are adjustable by one or more dampers 252, for example, e.g., the damper(s) 252 vary the amount of air which is allowed to enter into and be supplied by the supplemental air fan 142 to the pair of discharge nozzles 202. As such supplemental air fan 142 and its operation and function are conventional and well known in the art, a further detailed discussion concerning the same is not provided. The supplemental air fan 142 is coupled to and controlled by the burner control system in a conventional manner.

As is also conventional in the art, a cylindrical blast tube 254 encases and surrounds the fuel supply conduit 114 and the fuel discharge orifice 215 as well as the ignition components. The blast tube 254 typically has a diameter of between about 2.5 to about 8, more preferably a diameter of about 4±1 inches and a length of about 4 inches to about 10, more preferably a length of about 7±2 inches. As is also conventional in the art, a mounting flange 256 is supported by the exterior surface of the blast tube 254 and this flange 256 has a plurality of mounting apertures 258 formed therein (see FIG. 12B) which assist with mounting the flange 256 to an outer surface of a burner box 206 so that a leading outlet end 257 of the blast tube 254 can extend into and be located within the burner box 206 at a desired location spaced from the rear wall of the burner box 206. Preferably the flange 256 is adjustably mount to the exterior surface of the blast tube 254 so as to facilitate adjustment of the extent that the leading outlet end of the blast tube 254 is permitted to protrude into the burner box 206.

As is also conventional in the art, a component support plate 260 is accommodated within the blast tube 254 for supporting the various components (see FIGS. 13A and 13B), e.g., the fuel supply conduit 114 and the fuel discharge nozzle, and the ignition components. According to the present invention, the support plate 260 is modified somewhat for supporting the additional components of the present invention, e.g., the pressurized air supply conduit 134 and the pair of discharge nozzles 202. The support plate 260 typically has at least a plurality of spacer legs 262, e.g., typically three spacer legs, which assist with maintaining the support plate 260 centered within the blast tube 254. The support plate 260, in turn, centers and spaces the ignition components, the liquid fuel and the compressed air supply conduits 114, 134 and the pair of discharge nozzles 202 from the blast tube 254 and also redirects and channels a majority of the supplemental air, supplied by the supplement air fan 142, radially outward and around the support plate 260 as well as the supported components. The support plate 260 may have one or more small holes or other passages 264 formed therein, e.g., between 1 and 3, which permit only a small portion of the supplemental air, supplied by the supplemental air fan 142, to pass therethrough and flow toward the pair of discharge nozzles 202.

As is also conventional in the art, a flame retention head 266 is supported by and partially accommodated within the leading outlet end of the blast tube 254 (see FIGS. 12B, 14A and 14B). The flame retention head 266 supports a plurality, e.g., typically between about 4 and 12, radially inclined and inwardly extending deflectors 268 which are arranged to deflect some of the supplemental air, supplied by the supplemental air fan 142, and a further discussion concerning the purpose of the same will follow below.

As is conventional in the art, the flame retention head 266 has a plurality of spaced apart peripheral air outlets 270, e.g., typically between about 2 and about 15 and more preferably about 6-8 peripheral air outlets 270, formed in an outer periphery thereof. It is be appreciated that the overall design characteristics of the flame retention head 266 are dictated somewhat by the burner box 206 and the characteristics of a remainder of the burner system. The peripheral air outlets 270 are generally equally spaced about the circumference of the flame retention head 266 so as to funnel and generally slightly accelerate the supplemental air, supplied thereto, directly into the burner box 206 and provide supplemental air which assists with substantially complete combustion of the fuel mixture as it burns and is consumed within the burner box 206.

As noted above, the flame retention head 266 supports a plurality of radially inclined and inwardly extending deflectors 268. As is conventional in the art, each one of the radially inclined and inwardly extending deflectors 268 has a bent region or surface 272 so that when a portion of the supplemental air, which is supplied by the supplemental air fan 142, contacts the bent surface 272 of the deflectors 268, such air is caused to rotate or spin in either a clockwise or a counter clockwise direction, depending upon the direction in which the deflector surface 272 is bent. Such rotation of the supplemental air has a tendency to swirl or spin the flame BF in either a clockwise or a counter clockwise direction and this, in turn, has a tendency to center the flame within the burner box 206 and cause the flame BF to be tighter, denser and more compact. Such adjustment of the flame further by swirling or spinning supplement air assists with substantially complete combustion of the fuel mixture prior to the fuel byproducts being exhausted from the burner box 206 up the flue or chimney C.

According to the present invention and contrary the prior art, the plurality of radially inclined and inwardly extending deflectors 268, for deflecting some of the air supplied by the supplemental air fan 142 radially outward away from the flame, are inclined a further distance away from one another so that the radially inclined and inwardly extending deflectors 268 are modified to deflect somewhat less supplemental air while allowing more air to pass through a central aperture 274 and interact with the flame BF without being either spun or swirled. The additional inclination of the radially inclined and inwardly extending deflectors 268 is generally required because of the pair of discharge nozzles 202 have a wider liquid fuel spray pattern and thus the central aperture 274 through the flame retention head 266 must have a larger diameter to ensure that none of the emitted liquid fuel contacts any of the radially inwardly arranged deflectors 268, which generally leads to the creation of soot and/or the unburnt fuel.

A cylindrical air deflector sleeve 276 is also accommodate within the blast tube 254 (see FIG. 12B). The air deflector sleeve 276 is arranged generally concentric with the blast tube 254 and the support plate 260 and is provided to separate the blast tube 254 from the various burner components, e.g., the ignition components, the liquid fuel conduit 114 and the compressed air supply conduit 134 and the pair of discharge nozzles 202. A first end 278 of the air deflector sleeve 276 is located closely adjacent to the component support plate 260, e.g., is generally spaced therefrom by a distance of about a 1/16 of an inch to about ¼ of an inch or so, so as to form an annular gap 280 therebetween which generally extends around the perimeter of the component support plate 260. The air deflector sleeve 276 typically has a diameter which is generally the same size as the diameter of the component support plate 260. It is to be appreciated that the air deflector sleeve 276, alternatively, may have a diameter that is slightly larger than the component support plate 260 so that the air deflector sleeve 276 could extend over and surround the component support plate 260 and form the annular gap 280 therebetween or the air deflector sleeve 276 may have a diameter that is slightly smaller than the component support plate 260 and be spaced from the component support plate 260. This annular gap 280, between the support plate 260 and the first end of the air deflector sleeve 276, provides a small annular opening through which some of the supplemental air, supplied by the supplemental air fan 142, is permitted to flow and be supplied directly to the pair of discharge nozzles 202 to assist with combustion. The supplement air which flows in through this annular gap 280 is useful in supplying supplemental air to the pair of discharge nozzles 202 which assists also with cooling the discharge nozzles 202 and maintains them at a relatively low operating temperature.

The air deflector sleeve 276 typically has an axially length of three to four inches, for example, and generally extends from the support plate 260 to the flame retention head 266. The air deflector sleeve 276 is generally connected to the flame retention head 266, at a location between the peripheral air outlets 270 and the radially inclined and inwardly extending deflectors 268. The supplemental air which flows along toward the flame retention head 266, and is confined within the air deflector sleeve 276, abuts against but is generally not able to pass through the flame retention head 266. Consequently, such supplemental air is diverted radially inward, by the radially inclined and inwardly extending deflectors 268, and swirled or spun by the bent surfaces 272 as some of this air passes through the central aperture 274. Due to this arrangement, a majority of the air supplied by the supplemental air fan 142 passes between the exterior surface of the air deflector sleeve 276 and inwardly facing surface of the blast tube 254 toward the flame retention head 266 and is exhausted out through peripheral air outlets 270 of the flame retention head 266. That is, typically between about 90% to about 97% of the supplemental air is redirected by the component support plate 260 and the air deflector sleeve 276 and flows toward the peripheral air outlets 270 of the flame retention head 266 while only between about 3% and 10% of the supplied air either passes through the openings 264 in the component support plate 260 or through the annular gap 280 formed between the component support plate 260 and a first end of the air deflector sleeve 276, and thereafter flows toward the pair of discharge nozzles 202. The supplemental air, which passes through the openings 264 in the component support plate 260 or through the annular gap 280, assists with cooling the discharge nozzles 202 and also with inducing a swirling or spinning motion of the supplemental air, as this supplement air contacts the bent surface 272 of the deflectors 268 of the air retention head 266. Such swirling or spinning supplemental air assists with centering the flame BF within the burner box 206.

It is important to control the amount of supplemental air which flows through the annular gap 280 and directly communicates with the pair of discharge nozzles 202. During operation of the burner, it is desirable to maintain the flame BF as close as possible to but spaced a small distance from the pair of discharge nozzles 202, e.g., the flame BF is typically spaced about a quarter of an inch or so away from the discharge nozzles 202. Such spacing of the flame BF from the pair of discharge nozzles 202 generally results in the generation of an efficient flame, e.g., a blue flame, while also preventing the discharge nozzles 202 from becoming fouled and/or overheated during operation of the burner system.

Turning now to FIGS. 15A-18, a further detail description concerning the features of the discharge nozzles 202 will now be provided. As briefly discussed above, the liquid fuel is supplied, via the liquid fuel conduit 114, to a single liquid fuel inlet port 282 generally provided in a rear surface 284 of the nozzle housing 204 while the pressurized air is supplied, via the pressurized air conduit 134, to a single pressurized air inlet port 286 generally provided in the rear surface 284 of the nozzle housing 204. The pressurized air conduit 134, after entering into the discharge nozzle housing 204 through the air inlet port 286, divides into two separate pressurized air flow conduits 134 and each separate flow conduit 134 communicates with a respective one of the pressurized air orifices 217. Similarly, the liquid fuel conduit 114, after entering into the discharge nozzle housing 204 via the liquid fuel inlet port 282, divides into two separate liquid fuel flow conduits 114 and each separate flow conduit 114 communicates with a respective one of the liquid fuel discharge orifices 215. The supplied liquid fuel and the supplied pressurized air both eventually enter into one of the fuel discharge nozzles 202 where the two fuel components are discharged and thereafter intimately mix with one another and a further discussion concerning the same is now provided.

As can be seen in FIGS. 17 and 18, for example, each of the pair of the discharge nozzles 202 generally comprises a pairs of concentric discharge openings, namely, a centrally located liquid fuel discharge orifice 215 as well as an air discharge orifice 217 surrounding and being located concentrically therewith. That is, for each of the pair of the discharge nozzles 202, a removable cover or cap 288 engages with and closes off the discharge end of the respective discharge nozzles 202 and a threaded ring 289 engages with a mating thread and retains the removable cover or cap 288 in position. The removable cover or cap 288 has a relatively large opening 290 formed therein. A cylindrical extension 292, defining the liquid fuel orifice 215, passes completely through this relatively large opening 290 and the remote end thereof defines the liquid fuel discharge 215 which communicates with one of the two separate liquid fuel flow conduits 114. The liquid fuel flows along one of the two separate liquid fuel flow conduits 114 along one of the two cylindrical extensions 292 and out through the respective liquid fuel discharge orifice 215 and into the burner box 206 for mixing with the supplied air. The air discharge orifice 217, in turn, is defined by the inwardly facing surface 294 of the opening 290 formed in the removable cover or cap 288 and the outwardly facing surface 296 of the cylindrical extension 292 of the liquid fuel discharge orifice 215.

It is important to note that the removable cover or cap 288 defines a plane

PL which separates the pressurized or compressed air from an interior space of the burner box 206 while the fuel discharge orifice 215 passes axially through and past this plane PL by a small distance, e.g., typically between 0.002 to about 0.020 of an inch and more preferably a distance of between about 0.003 and about 0.005 of an inch. As a result of this, both the fuel discharge orifice 215 and the pressurized air discharge orifice 217 discharge their respective fuel components directly into the burner box 206. That is, the liquid fuel component is directly discharged into the burner box 206 while the pressured air component is also separately discharged into the burner box 206 and, only once these fuel components actually enter into the burner box 206, is the liquid fuel atomized into a particle size of between about 30 to 35 microns, for example, and intimately mixed with the pressurized air to form a fuel mixture which is thereafter is consumed within the burner box 206 during combustion of the fuel mixture. As with the previous embodiments, the pressurized air component, as it is discharge from the pressurized air orifice 217, tends to create a vacuum which assists withdrawing, sucking and/or evacuating the liquid fuel component from the fuel discharge orifice 215 of the discharge nozzle 202 in addition to the pressure of supplied liquid fuel.

The pressurized or compressed air is generally discharged circumferentially about and around the liquid fuel discharge orifice 215 and the discharged pressurized air, along with the withdrawn, evacuated and/or sucked liquid fuel, are each separately discharged into the burner box 206 and then intimately mixed with one another. As a result of this, the liquid fuel is substantially atomized, upon being discharge from the respective liquid fuel orifices 215, and thus are immediately able to be rapidly or substantially instantaneously consumed and burned, within the burner box 206, while maximizing the generation of heat and still minimizing consumption of fuel.

The inventors have determined that the relative spacing of the end face of the liquid fuel discharge orifice 215 from the end face of the pressurized air discharge orifice 217 is important in determining the overall characteristics of the flame as the fuel components are emitted and consumed within the burner box 206. By having the end face of the liquid fuel discharge orifice 215 extend a small distance further into the burner box 206 than the end face of the pressurized air discharge orifice 217, such arrangement has a tendency of inducing desired atomization of the liquid fuel component while also facilitating the formation of a relatively compact and axially short flame which leads to improved combustion and minimizes the creation of soot.

As described above, by controlling the rotational speed of the supplemental air fan 142 and/or adjusting the position of the damper(s) 252 of the supplemental air fan 142, which adjustably controls the sizes of the air inlet openings to the squirrel cage of the supplemental air fan 142, one can readily control the axial and the radial dimensions of the flame burning within the burner box 206. However, the control that one has over the axial and the radial dimensions of the burning flame, by merely adjusting the rotational speed of the supplemental air fan 142 and supplied air flow, can be somewhat limited. The axial and the radial dimensions of the burning flame can also be adjusted by the spacing of the discharge nozzles from one another, the amount of supplemental air which is allowed to flow over the pair of discharge nozzles 202, the flow of pressurized or compressed air through the pressurized air discharge orifice 217, the relative spacing of the end face of the liquid fuel discharge orifice 215 relative to the end face of the pressurized air discharge orifice 217 as well as the other characteristics of the discharge discharge nozzles 202. It is to be appreciated that the discharge nozzles 202 can be designed to discharge the liquid fuel in a spray pattern with a desired discharge angle.

As discussed above, a flame detector 160 is normally positioned upstream of the electrodes 156, 158 and located for viewing and detecting the presence of a flame, in the area immediately in front of the pair of discharge orifice 202, to confirm whether or not a flame is present within the burner box 206. In the event that the flame detector 160 does not detect a flame, a lack of flame signal is then supplied, in a conventional manner, to the control unit which then interrupts the flow of liquid fuel and/or compressed air to the pair of discharge nozzles 202 and then again initiates ignition of the flame, in a conventional manner. However, in the event that the flame detector 160 does, in fact, detect the presence of a flame resulting from the combustion of the fuel mixture, then such presence is also conveyed to the control unit which allows the burner system to continue operating until a sufficient amount of heat is generated.

As illustrated in FIG. 20, the shape of the fuel discharge from the pair of discharge nozzles, according to FIGS. 15A-15D, is relatively short and fat. That is, the shape of the resulting flame BF is generally axially shorter and wider radially than the shape of the flame from a single discharge nozzle. The discharge angle A₁ of the spray nozzle of FIG. 20 typically ranges from between 15° to about 40° and more preferably between 22° and 30°. The spray pattern, and thus the flame generally has an axial length L₁ of between 6 inches and 18 inches or preferably between about 8 inches and about 12 inches and has a radial spread R₁ of between 5 inches and about 10 inches more preferably between about 6 to about 8 inches.

It has been found that an axially shorter, and radially wider flame, generated by the pair of discharge nozzles 202 shown in FIGS. 15A-15D for example, thereby increases the overall efficiency of the fuel mixture being consumed within the burner box 206. It is believed that the shorter, wider, more compact flame thereby results in substantially complete combustion of the fuel—e.g., substantially all of the BTUs contained within the fuel are extracted and given off from the fuel mixture—and this thereby results in efficient heating of the heat transfer element(s) of the conventional heating system.

With reference to FIG. 21, a further embodiment of the present invention will now be discussed. To simply the discussion concerning this embodiment, identical elements or features, previously discussed above, are provided with identical reference numerals. In all other respects, however, this embodiment is substantially identical to the previously discussed embodiment and thus a further discussion concerning the same is not provided.

According to this embodiment, the circulating section of the fuel supply conduit 114 is eliminated so that the liquid fuel, pumped by the fuel pump 112, is pumped directly to the nozzle housing 204 for discharge by the fuel discharge nozzles 202 into the burner box 206. In addition, an adjustable pressure regulator 298 is provided along the liquid fuel supply conduit 114, downstream and typically adjacent the pump 112, for adjusting the pressure and/or the flow rate of the liquid fuel being supplied by the pump 112 to the respective liquid fuel discharge orifices 215 of the fuel discharge nozzles 202 for discharge into the burner box 206. In addition, the air compressor 220 is affixed directly to the burner, on a side thereof opposite to the pump 114, to render the burner system more compact. In all other respects, this embodiment is substantially identical to the previously discussed embodiment and thus a further discussion concerning the same is not provided.

The pressurized air is preferably supplied by an air compressor, such as a Thomas Products Division air compression headquartered in Sheboygan, Wis. and sold as part number 918CA15. This compressor can provide a compressed air flow rate of between 150±75 cubic fee per minute. The air compressor typically supplies compressed air at a pressure of between 2 and 30 psi, for example, and the supplied compressed air, after passing through the air restrictor 248, is typically reduced to a pressure of between about 3.5 psi and 7.0 psi, more preferably to a pressure of about 6.0 psi, depending upon the burner requirements.

In the event that a burner system, according to the present invention, replaces an old existing burner, generally the old existing burner will first be removed for the burner box 206 and then the new burner system, according to the present invention, will be installed in place thereof in a conventional manner. Thereafter, the operator will, once all the components are hooked up to the new burner system in a conventional manner, start the burner and measure the stacked temperature of the exhaust fumes exhausting up the flue. If the stack temperature is too low, the operator will then increase the fuel flow rate (e.g., increase the size of the liquid fuel orifice 215 and/or increase the size of the fuel restrictor 216) so that additional fuel is supplied to the burner box 206 and this will generally increase the temperature of the exhaust fumes exhausting from the burner box 206 through the flue. However, in the event that the flame extends to and reaches the opposed rear wall of the burner box 206 (this is typically checked by a visual inspection of the burner box 206), the operator will then reduce the flow rate of the pressurized or compressed air (e.g., decrease the pressure of the supplied pressurized or compressed air, decrease the opening size in the removable cap or cover 288 and/or decrease the size of the air restrictor 248), which assists with withdrawing the fuel out of the discharge nozzles, and this typically reduces or shortens the overall length of the flame and thereby assists with adequately spacing the leading end of the flame from the opposed rear wall of the burner box 206.

In the event that this stack temperature is still too low, the operator will again increase the flow rate of the fuel (e.g., again increase the size of the liquid fuel orifice 215 and/or increase the size of the fuel restrictor 216) and adjust the flow rate of the pressurized or compressed air (e.g., either increase or decrease the pressure of the supplied compressed air, either increase or decrease the opening 290 size in the removable cap or cover 288 and/or increase or decrease the size of the air restrictor 248) in order to adequately space the flame from the rear wall of the burner. This process continues until the measured stack temperature is at or within a recommended stack temperature range suggested by the manufacture of the burner box 206, e.g., typically the stack temperature is about 300±100 degrees above the temperature of the room accommodating the burner system. That is, if the burner system is located in a basement of a facility which is at a temperature of 60° F., for example, then the desired stack temperature is normally about 360° F. or so.

It is to be appreciated that in the event that the leading end of the flame reaches the opposed rear wall of the burner, this generally results in soot being created and formed on the opposed rear wall of the burner box 206 and this has a tendency of decreasing the overall efficiency of the fuel being consumed within the burner. In addition, the generation of such soot within the burner box 206 forms a thin layer on the inner wall(s) of the burner box 206 which generally hinders heat transfer from the burner box 206 to the heating system for the building. Accordingly, the fuel mixture is discharged and consumed and the flame is adjusted so as to avoid the creation of any soot as well as maximize combustion of the fuel mixture while minimizing the creation of any CO during combustion.

Alternatively, if the stack temperature is too high, the operator will decrease the fuel flow rate (e.g., decrease the size of the liquid fuel orifice 215, decrease the pressure and/or flow rate of the liquid fuel and/or decrease the size of the fuel restrictor 216) and adjust the flow rate of the pressurized or compressed air (e.g., either increase or decrease the pressure of the supplied pressurized or compressed air, either increase or decrease the pressurized or compressed air orifice 217 and/or increase or decrease the size of the air restrictor 248) so that the flame remains adequately spaced from the opposed rear wall of the burner box 206, e.g., is adequately spaced therefrom by an inch or so. Such fine tuning adjustment procedure will continue until the measured stack temperature is at or within a recommended stack temperature range suggested by the manufacture of the burner box 206, as noted above.

It is to be appreciated that a “blue flame” is the hottest and most efficient flame, a “white flame” is generally a fairly clean and efficient flame, while a “yellow flame” is generally the most inefficient flame and such inefficient flame typically results from supplying excessive fuel to the burner box 206. The preferred flame is a blue flame which has a temperature generally between 1,800 and 2,400° F., typically between 2100 to 2200° F. When such flame is present in the burner box 206, the exhaust gases flowing up the flue from the burner box 206 typically have a CO content less than 0.01 parts per million (ppm) and more preferably a CO content approaching 0.00 ppm and a CO₂ content of at least about 8 to 9.5 ppm and more preferably a CO₂ content approaching between about 14.3 and about 14.8 ppm.

Following adjustment of the stack temperature, the operator will then adjust the airflow rate of the supplemental air being supplied by the supplemental air fan 142 to the burner. This is done by monitoring the CO content in the exhaust gases being emitted from the burner box 206 and flowing through the flue. According to the present invention, as noted above, the desired CO content is approaching 0.00 ppm and the rotational speed of the supplemental air fan 142 and/or the damper(s) 252 of the supplemental air fan 142 are controlled so as to maximize the amount of CO₂ being exhausted from the burner box 206 as well as minimize the amount of CO which is created during combustion of the fuel mixture in the burner box 206. It is to be appreciated that the burner typically needs additional supplementary air to facilitate substantially complete combustion of all of the supplied fuel. However, if excessive supplemental air is supplied to the burner box 206, this additional air has a tendency to result in incomplete combustion of the fuel contained within the burner box 206 and such incomplete combustion results in an increased amount of CO being emitted from the burner box 206. To compensate for this, the operator will adjust the damper(s) 252 to decrease the amount of supplemental air being feed to the supplemental air fan 142. This decrease in the supplemental air flow rate allows the combustion products to “dwell” within the burner box 206 for a slightly longer duration of time, thereby promoting a more complete combustion of the fuel components while still minimizing the amount of CO generated during combustion.

It is to be appreciated that in order for the burner box 206 to operate properly, the burner box 206 should operate at a slight positive pressure, e.g., a positive pressure of about 0.04 psi to 0.06 psi, for example. As a result of such slight positive pressure, there is a natural draft or flow of the consumed fuel mixture components, from the burner box 206 and into the flue, and this further assists with substantially complete combustion of all of the liquid fuel and the air.

Each of the discharge nozzles is preferably a replaceable spray nozzle in which the size of the liquid fuel discharge orifice 215 and/or the pressurized air discharge orifice 217 can be readily change as necessary. Each spray nozzle is preferably an Special Twin XA Assembly automatic spray nozzle (manufactured by BETE Fog Nozzle, Inc. of Greenfield, Mass. 01301 USA) which is conventionally used to atomize a fluid, e.g., water or foam, to be emitted from a sprinkler system, for example. The inventors have determined that such automatic spray nozzle sufficiently mixes a liquid fuel component with an ample supply of supplemental air, such as the pressurized or compressed air which, in turn, atomizes the liquid fuel upon discharged from the pair of discharge nozzles 202. The discharge orifices 215, 217 for both the liquid fuel component and the pressurized air component are generally quite small to provide the desired atomization of the fuel mixture but can be modified, as desired, depending upon the particular application. For example, the liquid fuel component may have a liquid fuel discharge orifice 215 which has a diameter of 0.0016 of an inch (if a FC7 Liquid Cap is utilized), a diameter of 0.0026 of an inch (if a FC4 Liquid Cap is utilized), or a diameter of 0.0028 of an inch (if a FC3 Liquid Cap is utilized) while pressurized air discharge orifice 217, defined by the annular spacing between the opening 290 in the removable cap 288 or cover, a radial width of preferably greater than about 0.0014 of an inch and more preferably about 0.0070 of an inch. Typically the liquid fuel orifices 215, for each of the pair of discharge nozzles 202, are spaced apart from one another by a distance of about 1±about ¼ inch but it is to be appreciated that other spacing for the pair of discharge nozzles 202 are also possible.

The following is very brief description of wiring diagram shown in FIG. 19 of the drawings.

Line A extends between Fuel Primary and a Hot Bus Bar B;

Hot Bus Bar B;

Line C extends between Fuel Primary and a Neutral Bus Bar D;

Neutral Bus Bar D;

Line E extends between Supplemental air fan and Hot Bus Bar B;

Line F extends between Supplemental air fan and Neutral Bus Bar D;

Line G extends between Solenoid and Hot Bus Bar B;

Line H extends between Solenoid and Neutral Bus Bar D;

Line I extends between Compressor and Hot Bus Bar B;

Line J extends between Compressor and Neutral Bus Bar D;

Line K extends between Coil and Neutral Bus Bar D;

Line L extends between Coil and Hot Bus Bar B;

Line M extends between Power Supply and Hot Bus Bar B;

Line N extends between Power Supply and Fuel Primary;

Line O extends between Power Supply and Fuel Primary;

Line P extends between Supplemental air fan and Ground Bus Bar;

Line Q extends between Compressor and Ground Bus Bar;

Line R extends between Solenoid and Ground Bus Bar;

Line S extends between Fuel Primary and Flame Detector; and

Line T extends between Fuel Primary and Float SwitchNaive;

Since certain changes may be made in the above described improved fuel combustion system, without departing from the spirit and scope of the invention herein involved, it is intended that all of the subject matter of the above description or shown in the accompanying drawings shall be interpreted merely as examples illustrating the inventive concept herein and shall not be construed as limiting the invention. 

1. A burner system for burning a fuel mixture, the burner system comprising: a pair of discharge nozzles each having a liquid fuel orifice and an air orifice located concentrically with the liquid fuel orifice; a liquid fuel conduit being coupled to the pair of discharge nozzles for supplying a liquid fuel to each one of the liquid fuel orifices; an air conduit being coupled to the pair of discharge nozzles for supplying a pressurized air to each one of the air orifices; a pressurized air source being connected with the air conduit for supplying the pressurized air to the air conduit; the liquid fuel being supplied to the pair of discharge nozzles completely separate from the pressurized air so that the liquid fuel only mixing with the pressurized air, to form the fuel mixture, once the liquid fuel and the pressurized air are discharged from the liquid fuel and the air orifices; a supplemental air fan for supplying supplement air to the pair of discharge nozzles to facilitate substantially complete combustion of the fuel mixture; and an igniter for igniting the fuel mixture following discharge from the pair of discharge nozzles.
 2. The burner system according to claim 1, wherein a blast tube surrounds the pair of discharge nozzles and an air deflector sleeve is accommodate within the blast tube, the air deflector is located concentric with the blast tube and separates the blast tube from at least the pair of discharge nozzles and the air deflector sleeve is arranged so as to divert some of supplemental air, from the supplemental air fan, to flow toward the pair of discharge nozzles while directing a remainder of the supplemental air to flow along the blast tube, between the air deflector and the blast tube, and be discharged directly into the burner box.
 3. The burner system according to claim 2, wherein a component support plate supports at least the liquid fuel conduit, the air conduit and the pair of discharge nozzles, the support plate redirects and channels a majority of the supplemental air, supplied by the supplemental air fan, away from the pair of discharge nozzles, and a first end of the air deflector sleeve is located closely adjacent to the component support plate so as to form a gap therebetween, which permits some of the supplemental air, supplied by the supplemental air fan, to flow therethrough and be supplied to the pair of discharge nozzles.
 4. The burner system according to claim 3, wherein blast tube has a flame retention head at an outlet end thereof, the air deflector sleeve has a diameter which is generally the same size as a diameter of the component support plate and the air deflector sleeve extends axially from adjacent the component support plate to the flame retention head so as to prevent a majority of the supplemental air from flowing toward the pair of discharge nozzles.
 5. The burner system according to claim 1, wherein the liquid fuel orifice is centrally located within the pressurized air orifice and extends through the pressurized air orifice by a distance of at least 0.002 of an inch so that the liquid fuel only mixes with the pressurized air upon discharge from the respective liquid fuel and pressurized air orifices.
 6. The burner system according to claim 1, wherein the liquid fuel conduit is connected to a liquid fuel storage tank which stores a supply of the liquid fuel, and the liquid fuel is supplied from the liquid fuel storage tank to the pair of discharge nozzles at a pressure of between about 0.5 psi and about 2 psi.
 7. The burner system according to claim 6, wherein at least one valve is provided along the liquid fuel supply conduit for interrupting a flow of the liquid fuel from the liquid fuel storage tank to the pair of discharge nozzles when the burner system is inactive, and a liquid fuel pump is provided for pumping the liquid fuel from the liquid fuel storage tank to the pair of discharge nozzles.
 8. The burner system according to claim 1, wherein the pressurized air source is an air compressor which supplies compressed air at a pressurize of between 2 and 30 psi.
 9. The burner system according to claim 7, wherein the liquid fuel pump pumps the liquid fuel from the liquid fuel storage tank along the liquid fuel conduit at a flow rate of between about 1 gallon per minute to about 4 gallons per minute and at a pressure of between about 70 psi to about 300 psi, and the liquid fuel conduit has a fuel restrictor which reduces a pressure of the supplied liquid fuel to a pressure of between 0.5 psi and 2 psi.
 10. The burner system according to claim 8, wherein the pressurized air conduit has an air restrictor therein for reducing the pressure of the pressurized air being supplied by the air compressor, and the air restrictor has an opening therein of between 0.0020 and 0.0040 of an inch so that the air restrictor reduces the pressure of the pressurized air to an air pressure of between about 3.5 psi and 7.0 psi.
 11. The burner system according to claim 4, wherein a second end of the air deflector sleeve is connected to the flame retention head so as to redirect, any supplemental air which passes through the gap, through a central aperture of the flame retention head.
 12. The burner system according to claim 1, wherein the igniter comprises a pair of electrodes, located adjacent and downstream of the pair of discharge nozzles, for igniting the fuel mixture following discharged from the pair of discharge nozzles.
 13. The burner system according to claim 1, wherein a flame detector is located adjacent the pair of nozzles for detecting a presence of a flame generated by combustion of the fuel mixture.
 14. The burner system according to claim 12, wherein the flame retention head has a plurality of radially inclined and inwardly extending deflectors and a plurality of spaced apart peripheral air outlets located radially about the radially inclined and inwardly extending deflectors, and the radially inclined and inwardly extending deflectors are arranged to swirl some of the supplemental air, supplied by the supplemental air fan, to assist with swirling the fuel mixture, following discharge from the pair of discharge nozzles.
 15. The burner system according to claim 12, wherein a second end of the air deflector sleeve is connected to the flame retention head, between the plurality of spaced apart peripheral air outlets and the radially inclined and inwardly extending deflectors, so as to redirect any supplemental air through a central aperture of the flame retention head.
 16. The burner system according to claim 1, wherein a pressurized air solenoid valve is located along the pressurized air supply conduit for interrupting a flow of the pressurized air to the pair of discharge nozzles when the burner system is inactive, and at least one liquid fuel solenoid valve is located along the liquid fuel supply conduit for interrupting a flow of the liquid fuel to the pair of discharge nozzles when the burner system is inactive.
 17. A burner system for burning a fuel mixture, the burner system comprising: a pair of discharge nozzles each having a liquid fuel orifice and an air orifice located concentrically with the liquid fuel orifice; a liquid fuel conduit being coupled to the pair of discharge nozzles for supplying a liquid fuel to each of the liquid fuel orifices; an air conduit being coupled to the pair of discharge nozzles for supplying a pressurized air to each of the air orifices; a liquid fuel supply being coupled to the liquid fuel conduit for supplying the liquid fuel to liquid fuel conduit; a pressurized air source being connected with the air conduit for supplying the pressurized air to the air conduit; the liquid fuel being supplied to the pair of discharge nozzles completely separate from the pressurized air so that the liquid fuel only mixing with the pressurized air, to form the fuel mixture, once the liquid fuel and the pressurized air are discharged from the liquid fuel and pressurized air orifices; a supplemental air fan for supplying supplement air to the pair of discharge nozzles to facilitate substantially complete combustion of the fuel mixture; a blast tube surrounding the pair of discharge nozzles; an air deflector sleeve being accommodate within the blast tube, the air deflector being located concentric with the blast tube and separating the blast tube from at least the pair of discharge nozzles, and the air deflector sleeve being located so as to divert some of supplemental air, from the supplemental air fan, to flow toward the pair of discharge nozzles while channeling a remainder of the supplemental air to flow along the blast tube, between the air deflector and the blast tube, and be discharged directly into the burner box; a flame retention head being supported at an outlet end of the blast tube, a second end of the air deflector being connected to the flame retention head, and the air deflector sleeve prevents a majority of the supplemental air from flowing toward the pair of discharge nozzles; an igniter for igniting the fuel mixture following discharge from the pair of discharge nozzles; and a flame detector being located adjacent the pair of nozzles for detecting presence of a flame generated by combustion of the fuel mixture.
 18. A method of operating a burner system for burning a fuel mixture, the burner system comprising a pair of discharge nozzles each having a liquid fuel orifice and an air orifice located concentrically with the liquid fuel orifice; a liquid fuel conduit being coupled to the pair of discharge nozzles for supplying a liquid fuel to each one of the liquid fuel orifices; an air conduit being coupled to the pair of discharge nozzles for supplying a pressurized air to each one of the air orifices; a pressurized air source being connected with the air conduit for supplying the pressurized air to the air conduit; the method comprising the steps of: supplying the liquid fuel to the pair of discharge nozzles completely separate from the pressurized air so that the liquid fuel only mixing with the pressurized air, to form the fuel mixture, once the liquid fuel and the pressurized air are discharged from the liquid fuel and the air orifices; supplying supplement air to the pair of discharge nozzles, via a supplemental air fan, to facilitate substantially complete combustion of the fuel mixture; and following discharge of the fuel mixture from the pair of discharge nozzles, igniting the fuel mixture via an igniter; allowing the burner system to continue operating upon a flame detector detecting a presence of a flame generated by combustion of the fuel mixture. 